Getting through the gate is your primary goal. Exercise eg walk other times & places. Order the wheelchair when you purchase your ticket, they can pick you up right outside your car and take you all the way to the gate from where your plane leaves. Make a copy of your disability plastic sign that you using your car and have it with your ID just incase they ask or act like a$$holes and please just use the services available!! You are hurting yourself by walking, standing, bending over, sitting on the floor (all which I’ve done before) and then ending up miserable even before the plane leaves — which is probably the most uncomfortable portion of traveling — for me anyway. I’m not blaming you as the TSA response to you and behavior was wrong but as a person with an invisible disability, you need to pick your battles and remember your goal!!!! Using a wheelchair gets you through to the gate MUCH faster then walking. I promise you. I’m sorry you were dealing with what I am dealing with a day-to-day basis, it’s absolutely horrible.

FYI. I have the same history as you do but wore the brace from age 4 to 13 then surgery at 18, rod removal at age 29, disabled at 46. what’s different is that I managed my pain with exercise in the early years until at age 38 I was diagnosed with chronic Lyme disease which is when I applied for disability. But I wouldn't agree more with every description you’ve written about how you feel and how people have treated you because you “look” fine or normal.